1. Technical Field
The present invention relates to a defect inspection apparatus and a defect inspection method for inspecting a defect of an inspecting object on which a circuit pattern including group of lines is formed.
2. Background Art
In a semiconductor manufacturing process, foreign materials on a surface of a semiconductor substrate (wafer) will cause insulation failure of wiring, failure of short-circuiting or the like, and fine foreign materials will cause insulation failure of capacitor, breakage of a gate oxide film or the like. These foreign materials include: those that are generated from a movable section of a transfer apparatus; those that are generated from a human body; those that are reaction-generated in a processing apparatus by process gas; and those that are mixed in chemicals and material and they contaminate the surface of a semiconductor substrate in various states due to various causes. Moreover, even in a manufacturing process for liquid crystal display elements, if the foreign materials contaminate the pattern to cause some sort of defect, the liquid crystal display elements will not be used as display elements. Furthermore, the same circumstance can be expected in a manufacturing process for printed boards, and contamination by of foreign materials is responsible for short-circuiting of pattern and contact failure.
Japanese Patent Application Laid-open Publication Nos. Sho 62-89336 (FIG. 1, page 5, upper right column), Sho 63-135848 (FIG. 1), Hei 1-117024 (Claim 4), Hei 1-250847, Hei 6-258239, Hei 6-324003, Hei 8-210989, Hei 8-271437, and 2000-105203 disclose the techniques of detecting such foreign materials adhering to the surface of the semiconductor substrate. For example, in the technique disclosed in JP-A No. Sho 62-89336, a semiconductor substrate is irradiated with a laser to detect scattered light, which is generated from the foreign material when the foreign material adheres to the semiconductor substrate, and the detected result is compared with the preceding inspection result of the same type of semiconductor substrate. In this way, this technique eliminates a false alarm, which might be caused due to pattern, enables inspection of foreign materials and defects with high sensitivity and high reliability. Moreover, in the technique disclosed in JP-A No. Sho 63-135848, the semiconductor substrate is irradiated with a laser to detect scattered light from the foreign material on the surface of the semiconductor, and the detected foreign material is analyzed by analysis technique such as laser photoluminescence or secondary X-ray analysis (XMR).
Furthermore, as a technique for inspecting a foreign material, there is known a method of emphatically detecting a foreign material or defect having no repeatability while the surface of a semiconductor substrate (wafer) is irradiated with coherent light, and also while light emitted from a repetition pattern on the wafer is removed through a spatial filter. Moreover, JP-A No. Hei 1-117024 (Claim 4) discloses a foreign material inspection apparatus that detects a foreign material in such a way that a main group of lines of a circuit pattern formed on a wafer surface is irradiated with illumination light from a direction inclined at 45 degree to a direction of the main group of lines, while zero-order diffracted light from the main group of lines is prevented from being inputted to an aperture of an objective lens. JP-A No. Hei 1-117024 also discloses that a group of lines other than the main group of lines is shielded through the spatial filter. Furthermore, JP-A Nos. Hei 1-250847, Hei 6-258239, Hei 6-324003, Hei 8-210989, Hei 8-271437, and 2000-105203 disclose techniques relating to an apparatus for inspecting a defect such as a foreign material and a method for the same. In addition, JP-A Nos. Hei 5-218163 and Hei 6-258239 (FIG. 3) disclose an example of spatial filters.